Integrally molded plastic fastening elements of the types disclosed in U.S. Pat. Nos. 3,651,734 and 4,181,061 continue to gain commercial acceptance both here and abroad. These fastening elements comprise, in substance, a head for disposition at the end of an opening, typically a hole in a hollow wall, expansible locking means for location at the other end of the opening, and flexible, spaced apart connectors extending therebetween.
These fastening elements utilize relatively long connectors or legs which are expanded radially outward far beyond the edges of the opening when the fastening element is in its expanded locking position. Specifically, the locking means typically comprises a pair of toggle members pivotally connected together at their adjacent ends so that they are movable between a collapsed portion in which they can be inserted through an opening and an expanded position in which they secure the fastener within the opening. The connector elements or legs are joined to the toggle members at such locations on the toggle members that when the toggle members are moved into an expanded position, the connectors are forced relatively far radially outward from their radial location in the collapsed condition so that they extend radially outward far beyond the edges of the opening. U.S. Pat. No. 4,181,061, discloses an integrally molded plastic fastening element comprising a head portion, a longitudinally extending body portion having a pair of longitudinally extending pillar-like parts, and a pair of substantially rigid locking arms pivotally connected to each other at their adjacent ends. These rigid arms are pivotally connected to the body portion at the ends of the respective pillar-like parts at positions radially adjacent to the cross-section of the body so that the rigid arms bear the bulk of the load applied to the fastener. The advantages of this structure over U.S. Pat. No. 3,651,734 include enhanced load bearing capability and simplicity of structure. While the fastening elements of both previously cited patents have proved highly satisfactorily for a wide range of applications, the present invention is directed to a device having improved features relating to the modification of the connection of the expansible locking means to the other end of the fastening element.